As a side note: it's kind of an advertisement, no? Given that it is WIRED/Conde Nast, known for such blurring the lines between editorial and ads (they're pioneers in the "advertorial"), without info to the contrary I'll assume Tesla paid for this.

When I had my factory tour I asked about vehicle testing, particularly the water bath. I was told that not every car undergoes the full testing procedure, that they only sample a certain percentage of cars to be run through the full test, including the water bath.

Does anyone know if this has changed? My impression, based on my factory tour, is that the extensive 5 hour test is only on sampled cars, not every car.

I believe it is much cheaper to run vehicles through full test and discover problems early/fix them at the factory compared to shipping car to customer and dealing with problems at service center level later.

But it is plausible that when Tesla had end of quarter rushes that they were short on factory personnel to the point that they decided to offload QA to SC to archive higher production numbers during those few weeks. But generally it just make economical sense to fully test each unit at the factory.